This invention relates to sprocket wheels for use with link chains.
The invention is concerned with a sprocket wheel of the kind comprising a plurality of pockets around its periphery separated respectively by upstanding teeth, each tooth having a groove therethrough in a plane substantially normal to the axis of the wheel. The chain is engaged on the sprocket wheel with alternate links respectively lieing in the pockets and standing up in the groove. Such a sprocket wheel is hereinafter called "a sprocket wheel of the kind set forth".
Sprocket wheels of the kind set forth are often used with lever or chain hoists (hereinafter referred to as "manual hoists") for transmitting a lifting or carrying force through a load chain. In known sprocket wheels of the kind set forth, the pockets are recessed in the circumferential surface of the wheel and are complete, i.e. the walls of the pockets consist of two side walls and two end walls which completely encompass the pocket. Thus the pockets are dimensioned to the links of the chain which in turn must be of precise and consistent dimensions as occurs in chains known as "graded chains".
In known sprocket wheels of the kind set forth used in manual hoists, there are four or five pockets separated respectively by four or five upstanding teeth.